Polytrimethylene terephthalate fiber, which exhibits the pliability of nylon fiber and the mechanical properties of polyester fiber, is a fiber used for clothing applications because of its characteristically excellent stretchability (easy elongation and easy recovery after stretching).
Currently in the field of clothing manufacture, fabrics (hereinafter, a fabric includes a woven fabric and a knitted fabric) composed of polytrimethylene terephthalate fiber are subjected to “fabric dyeing”, which is dyeing of the fabric, in order to obtain fabrics with an excellent soft feel and stretchability.
Fabric dyeing, however, has had a drawback in that it cannot produce fabrics with an excellent fashionable sort of high-quality, which are instead obtained by forming patterns through color arrangements between yarns. This has led to increased demand for fabrics made of dyed yarn, with the fabrics being woven or knitted by the yarn after dyeing; however, dyed yarn exhibiting the original soft feel and stretchability of polytrimethylene terephthalate fiber and excellent dimensional stability suitable for fabric purposes has not yet been achieved.
With fabric dyeing, fabrics exhibiting excellent stretchability and excellent bulkiness can be obtained using polytrimethylene terephthalate fiber crimped by yarn working such as false twisting. However, the crimp elongation is insufficient when using dyed yarn obtained by ordinary methods that employ polytrimethylene terephthalate fabric crimped by yarn working such as false twisting, and when such yarn is used for fabrics, the resulting fabrics have inferior stretchability and bulkiness compared to fabrics obtained by fabric dyeing. For this reason there has been a demand for dyed yarn with high crimp elongation, which can provide fabrics having excellent stretchability and bulkiness.
On the other hand, cellulose-based fiber and wool fiber both have excellent moisture absorption and a characteristic feel, and are therefore in high demand for dyed yarn. Nevertheless, when cellulose-based fiber or wool fiber is used alone in fabrics, the dimensional stability is inferior and wrinkles tend to develop.
In order to solve such problems, Japanese Unexamined Patent Publication (Kokai HEI) No. 8-170238 and other publications have proposed combining regenerated cellulose fiber and polyester fiber. However, while combination with polyester fiber improves the dimensional stability and wrinkle resistance, a harder feel tends to result, or else the feel becomes that of polyester, thereby significantly impairing the feel of the cellulose-based fiber or wool fiber, while the stretchability is also inadequate.
A demand has therefore existed for dyed yarn exhibiting the feel of cellulose-based fiber or wool fiber, while also having excellent stretchability and dimensional stability.